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June 17, 1952 D. v. GALLERY, JR 226099400 GUN SIGHT Filed April 25, 1941 2 SHEETS- SHEET 1 l -4/ 2o L l I "J l :z: I /3 Ah 7 5 l 2l `J e 8 f- 45 l f. l n

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INVENToR Patented June 17, 1952 SIG-HT Daniel-.V1 Gallery, Jr., United.- StatesNavy.. Arrlieellenrrll 1941. SferielNa 3.8.9@44. wellne- (Chile-49.93

(Granted under. the act 011 Merch. 3j.

mangled. enel 1928.; .2110.; Q. e- 7.517..)

This. invention relates Y.to .automatically compensating gun.:slghts.-for -flexibly-.mounted aerial machne:.g'uns, .and more-.particularly t0 the time of-compensating-1-gun:sight described; and-11aimelg inmyaco-pendingilapplication. Serial; No, 3865090.. for..msrhettersfateat, meciMareh. 3l.. 19411,.new- Patent -2 .;534;25 granted Decembervlzl', .195,05-

lt- `is-an .obieetcf this. invention tie-prende; a new.y l113.116.; useful. means fior. introducing.. au c reeteninte one, .off-the. we .Sighting elemelel; Qf. -airereftmaehre gunde-order te 'compensate th?. 113g SYGPQ''S al? SPQQ@ '0n ctgryoffthellc 1 t. haverreasled. anew .fee-A ofeeere Dreef. the. .we Salbei lle-l-llnefe-.feight established b'y .lieseelemente ferm. allele with the. bprclof the` whenY the giunis, trained and elevated; at; anailelerelelire. te. lille-lere. @mail the.. airerel.-

The angleermed. by. .et the .eighteen tleexi-O the bereflhereua may be d elled in teme.. ef. we. angles., -eaell lieltlred..- by .Dreeelne thefillxle.. Qieieliterd f the here. @all Q- Plane? ills. ing. Igllf'- lglsr Qn@ er. the' .planes centaine. athwarshp. alle longitudinal axis of the aircraft and "is hereinf after referred.. te. ai the herlzentel reference plane; the other plane., contains the 'lenltllslnel iiae'f. the. aimait.. 'ersliehereirafler reifer. .d as...theYerealyreereaeeaclara. The t. ...de Ggf-telle. angle. @medley the .lille eff eight and elle-arie. far-trie Ahere ef; 'the gun ie dependent upon 'the air lspeedofthe'lijirigV aircraft and algo uieeathe. aasleefzelecellen endtreie-ef-me elle relativeeto the longitudinal agis of; Said aircraft,

'flori the purpose of- Ithis zdisclosure it will .be aeemnedxthat. euring firing :the 'arerefe le flying ata constaptspeedfand that-the sighting-mem; bers are proper-ly spacedvfor the .lnwn airspeed oQf-the aircraft. iE-f theaxis ofthe bore of the Ygunjis 1tparallelV to the -plane or the` longitudirial and'athwartship agiis off Viche aircraft, which fie. the `pes.iti r.1g .ef fzere eleratlea the. -ef feet'` Cif-the airspeedofi the moving 'laire-rait 4Von the .treieetery veli-the heller. will elianee aeree gunjis efnoveclf in--trainabqut ita azimuthalfaxis.. For `'the positionof zero train the axis 'fot the bore ofv the --gun will 'lbe -parallel `to the longitudinal -or 1fore 'andate axis Aoli the aircraft, and the Vmuzzle of -the..-gun will be Lpointerl the ldirection ofdlight. Invathisfpositionlthe air-speed or "the lringlaircrat wouldV YVbe added directly to lthe muzzle :v elfacityeci?` the V:bullet and! .would cause f-no distortion in the :bullets y.-Im1mal trajectory. .Consequently nov correction Woulck lie, applied. t9 the/sightsftov .compeusatevv-lfor t effeet of the airspeed, because inthe rangeshcyfel. which these sightsV areeffective the trajectoryis substantially flat.

fleetiea will.' e115.. feeuree bel dere i eirepeleserd .the elleleefrtraip. 'rhedireet 1.1 ef; tnereelllieni pain. @,f. the. bulle-,rimarra del'- ned in terms of the alriglefhetween 'thie u sultant path and the normal trajectory which would be inline .with the arie o f the bore. This angle, which I'vhave. indica-tedv as t, may be @wel elle.. aaele-eff-de1leetlen train .endie eggltg Y@ eine. at.

Verl-Va cosel.

l i M a the airspeeci ofthe vfiring air crafMtqlb` ist-he anglefoftrain, and- Vais" the fm'uzzlel velocity of tllbullet. It is apparent'frcr'n which iis-the maxi-:num angle of dellection.

It lis thus noted-that ftl'lfe. magnitude for"r the angle of deflection in train qst tvaries fron'zero atan angle ofgtrainegual to `ero `to a inaiii'rr'im value Vat angle of train equal to 96.; -to zero agai-nwhen the angle of. train is 1.80%, and.l inaxi mum.again;for...an angle oftrain which is rJequal een?" to 270. Therefore, in order to correct forthis 3 angle of deflection, I propose to offset the axis of the bore of the gun from the line of sight by an equivalent angle of moving one of two sighting members in a path parallel to the horizontal reference plane and in a direction perpendicular to the axis of the bore. It is apparent that if the sinevfunction of the angle of Itrain at is applied to one of the sight elements the angular offset formed by the two sighting elements would be correct for all angles of train.

Corrections must also be introduced into the sight angle to compensate for the effect of the ring aircrafts airspeed on the velocity and trajectory of the bullet for different angles of elevation of the gun. Consider, for example, that the gun is in a position of zero train but elevated at an angle ae. The angle of deflection in elevation pe which is the vertical angle between the resul tant path of the bullet and the axis of the bore, (or the angle which is formed between the resultant trajectory and the axis of the bore when projected' upon the vertical-reference plane) is equal to Va sine ae Vg-l-Va cos -ae It is apparent from the equation that as the angle of elevation is changed with the gunremaining at zero angle of train, the correction which should be introduced into the sighting element would vary as a function of the sine of the angle of elevation ae, This correction is, however, influenced by different angles of train. For an angle of train other thany zero the component of the firing aircrafts airspeed in the plane normal to the horizontal reference plane containing the axis of the bore, is equal to the airspeed multiplied by the cosine of the angle of train (Va cos. at) .y It is this component of velocity which when acting upon the bullet in flight produces the vertical offset, because the vertical projection of the resultant velocity is equal to the vector sum of Vg and`Va cos. at. Therefore, for all angles of elevation and train the angle of deflection in elevation eis equal to Va cos at sin ae Vg--Va cos at cos ae If it is considered that ae remains fixed as the gun is moved in train, 45e will vary to a maximum value when at is zero, to zero when at is 90; maximum again when at is 180, and to Zero again when `at equals 270. Thus, in order to correct forthe angle of deflection in elevationgbe one of the sight elements must be moved in a path parallel to .the vertical reference plane and'perpen-y dicular to the axis of the borean amount which is a function of the product 'of the sine of the 4angle of elevation and the cosine of the angle of train.

It is, therefore, a specific object of this invention to provide a means'V for moving one of two sighting elements in apath parallel to thehorizontal reference plane and normal to the axis of the bore an amount which is a function of the sine of angle Iof train, and for moving the same sighting element in a path parallel to the vertical reference plane 'and normal to the axis of the bore of the gun an amount which is a function of the product of the sine of the angle of elevation and the cosine of the angle of train.

` With the foregoing and other objects -in view, theinvention consists inthe construction, combination and arrangement ofparts hereinafter described and illustrated in the drawings, in

which:

tan-1 Fig. 1 is a diagrammatic illustration showing mechanical means for offsetting the front bead sight as the gun is moved in elevation and train. For the position of the sight, as illustrated, the gun elevation is zero and the angle of train is zero;

Fig. 2 is a diagrammatic Villustration showing a method for offsetting the sighting element by means of a three-dimensional cam;

Fig. 3 illustrates diagrammatically a means for offsetting the sighting element by means of two sine cams;

Fig. '4 graphically illustrates a method for offsetting the sighting elements by means of a log cosine and a log sine cam; and

Fig. 5 is a perspective View of the tiltable plate and roller of Fig. 1.

Referring to Fig. 1 of the drawing showing a specific means for introducing the proper correction into one of two sighting elements as the gun is moved in elevation and train, the pedestal support for the gun is indicated generally at I0. A `yoke member II is secured tothis ipedestal support so as to be rotatable about'an azimuthal axis Y--Y to provide for movement in train. Suitable supports I2 for the gun trunnions I3 are provided on this yoke member so that the gun may be rotated about a lateraly axis X-X .through the trunnionsto provide for movement in elevation.

A'large ring gear I5 is secured to the yoke member II to form a driving engagement' with 'apinion gear I6 keyed to a rotary spindle II jour*- vnaled in a bushing I9 which is seated in the retaining block I8. This block I8 is bolted or otherwise secured tothe pedestal ID and the bushing I9Iis preferably formed about the spindle II so that when held in place in the retaining block IIB byV means of Ithe pin 2|, or other means, the spindle will be rotatably secured'within the supporting block and will be retained in place irrespective of the position ofthe aircraft upon which the gun may be mounted. The opposite end of the spindle Il is providedv with a socket connection which is adapted tov receive an end of a exible shaft indicated generally at '20. The collar 22 securely holds the drive shaft to the spindle.

As the gun is moved in train about the aziv muthal axis Y-Y, the large ring gear rotates with the gun and drives the piniongear IB which is rotatably secured to the block I8. The rotation of the ring gear drives the flexible shaft 20, which is coupled to a worm gear 23 at its opposite end. 'Ihis worm gear 23 yis in ,mesh with a worm wheel 24 integrally formed or rotatable with the train input wheel 25.` vThe train input wheel may be geared at its outer periphery so as to mesh with the .two gear wheels 26 and '21', each lof which carrya crank pin 29 and 28 respectively. The ratio between the yring gear I5, pinion gear I6, worm gear 23, and the gear wheels 24 and 25 are selected so that the train crank pins 28 and l29, rotate at a ratio of 1 tofl withfthe gun in train. A The adjustable bead sight 50 is xed to or formed integrally withrthe upper extremity of the control shaft 3U.Y This shaft extends'in a direction parallel to the vertical reference plane" but may be moved laterally with respect to the boreof the gun to move the bead sight in a path parallel to the horizontal reference plane and in a direction perpendicular to the axis of the bore. `In order that the movement of the bead sight may be a functionof the sine ofthe angleoftrain,l the shaft isslidably kheld in place 7.. y angle of train. Likewise, translatory movement of the cam along the aXis-a/-a will cause aY vertical movement of the beadand follower 60 which is a'function of the sine of vthe angle of elevation. Suitable mechanical connections, well known to the art, are provided to rotate the cam at a ratio of 1 to 1 as the gun is moved in train, similarly, other mechanicalconnections and devices well known in the art are provided to move the cam laterally on its axis a--a a distance equivalent to b-c for each movement of the gun in elevation through an arc of 90.` This translatory movement of the cam must be directly proportional to the rotary movement of the gun` in elevation.

The correct position of the follower 60 yfor an angular elevation of 90- and zero angle of train, is the point c indicated on the drawing. The follower 60 in this position transmits the maximum vertical displacement to the bead as the cam surface is rotated in response to movement of the gun in train. When the elevation of the gun is zero and the train iszero the correct position of the followerV is at the point b on the drawing. The cam surface is cylindrical at this point so that the bead sight will not be moved along its vertical path as the gun is moved in train. If the gun is trained 90 the component of the air speed of the firing aircraft along the bore or within the vertical plane of the bore is zero. Therefore, when the cam is rotated 90 from the position shown in the drawing to correspond to the position of train equal to 90, no vertical movement will be transmitted to the bead sight as the gun is moved in elevation, because the cam surface is at this point uniformly spaced from the axis af-a throughout the distance b-c.

If a turret mount is used wherein the gun may be moved in elevation throughout 360, the cam is merely shuttled back and forth along its axis a-a, once for each 90 movement in elevation. The particular apparatus for effecting the movement of the cam has not been disclosed, for the sake of simplicity of the drawing and because I am not here concerned with their details which involve only features of mechanical design, well known to the art.

In Fig. 3 I have diagrainmatically illustrated a method of introducing the sin. E cos. T function by means of two sine cams 6l and 62. modification the movement of the gun in elevation and train is transmitted directly to ltwo differentials 65, 66 so that the output of one (65) is equivalent to the sum of the two movements, while output from the other (66) is equivalent to their difference. That is, the output from differential 66 is equivalent to the movement of the gun in elevation minus the movement of the gun in train. The output from each differential is transmitted directly to one of each of the two sine cams 6l, 62. The translatory motion delivered to the follower B3 by the cam El' is a function of both the sine of the angle of elevation and the sine of the angle of train. The translatory motion transmitted to the follower 64 by the cam 62 is, however, a function of the sine of the angle of elevation-sine of the angle of train or sine (E-T) which is equal to sin. E cos. T-cos. E sin. T. The translatory motion of each follower 63, 64 is transferred into rotary motion by means of any of a number of mechanical arrangements well known in the art. This rotary motion which is the equivalent of the translatory motion of the two follower members is transmitted to another differential 61, Whose output is equivalent to the In this tion of my invention, wherein the properl correction to the bead is introducedby means of 4two log cams 1li-'H and an anti-log cam 12. yIn this modification the movement of the ygear Yin train is transmitted directly to the log cosine cam 'l0 so that the cam will rotate at a ratio of 1 to l with the gun in train. The movements ofthe gun in elevation is transmitted directly Yto Ya log sine cam Il which rotates with'the gun at a ratio of 1 to 1. The rotary movement of each cam is transmitted into translatory movement by means of the followers G8-69. Movement of follower 68 is equivalent to a function of the log cosine angle of train, and the translatory movement of the follower 69 is equivalent to a function of the log sine angle of elevation. The transla-v tory movement of each follower is transformed into an equivalent rotary movement by means of apparatus well known to the art and this'rotary movement is transmitted directly to a differential whose output would be equivalent to the sum of the log sine angle of elevation log `cosine angle of train or log sine E cos. T. This rotary movement is transmitted to an anti-log cam l2 whose output in translatory movement is equivalent to a function of the product of sine angle of elevation and cosine angle of train. This is the proper vertical compensation which must be introduced into the movement of the bead.

It will be apparent to those skilled in the art that while I have disclosed my invention with reference to a bead sight, the invention is not so limited, since obviously other equally useful sighting elements may be used. Furthermore, it should be understood that I do not propose to be limited specifically tothe type of gun mounting illustrated in Fig. 1. In fact, it is to be expressly understood that the present invention is not limited to any specfic means disclosed hereinor otherwise than by the appended claims The invention describedherein may be manu-` factured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Iclaim: l. A gun movable about elevational and azimuthal axes and having a movable sighting element, in combination, a pair of confronting plates, a pivotal mount for one of the plates and a structure at one of its sides defining a slot, a system of axially parallel rods, one of the rods carrying the sighting element and engaging the other plate, a second rod having roller contact with the confronting surfaces of the plates, a third rod having a lateral st ud riding in the slot structure to accommodate rocking of said one plate, a gear train and rmeans for setting it in operation by the training of the gun in azimuth, crank operated connections between selected gears of the train and the first and second rods for producing a lateral shift of said first and second rods and said other plate, and a terminal crank device for the` third rod, being operativeby` elevation of the gun for producing a unitary axial shift of the three rods accompanied by rocking of the pivoted plate and an axial movementI of the remaining plate.

2. A gun movable about elevational and azimuthal axes and having a movable sighting element, in combination, a pair of confronting plates, a pivotal mount for one of the plates and a structure at one of its sides defining a slot, a system of axially parallel rods, one of the rods carrying the sighting element and engaging the other plate, a second rod having roller contact with the confronting surfaces of the plates, a third rod having a lateral stud riding in the slot structure to accommodate rocking of said one plate, a gear train and means for setting it in operation by the training of the gun in azimuth, crank operated connections between selected gears of the train and the first and second rods, said crank connections including guideway terminals slidably containing the rst and second rods for lproducing a lateral shift of said first and 10 second rods and said other plate, a terminal crank device for the third rod, being operative by elevation of the gun for producing a unitary axial shift of the three rods accompanied by rocking of the pivoted plate and an axial movement of the remaining plate, and a spring between one of the guideway terminals and the plate of the first rod. establishing a unidirectional pressure in the rod system and the confronting plates to the terminal crank device.

DANIEL V. GALLERY, J n.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,650,628 Inglis Nov. 29, 1927 20 1,935,615 Coupland l Nov. 21, 1933 2,183,530 Alkan Dec. 19, 1939 2,466,093 Ford Apr. 5, 1949 

